如何将 c++ dll printf 导入 c# 文本框

Question

我希望使C++DLL与C#代码通信，但我无法让它工作，我必须从C++DLL导入"printf"消息以在C#文本框中打印，任何人都可以帮助我，只要它有效对我来说很好，有人可以指导我吗？我的主要优先事项是 C# 将能够在C++ DLL 中打印"printf"函数C++DLL 代码，但代码编译为 C：

ReceiverInformation()
{
     //Initialize Winsock version 2.2
     if( WSAStartup(MAKEWORD(2,2), &wsaData) != 0)
     {
          printf("Server: WSAStartup failed with error %ldn", WSAGetLastError());
          return -1;
     }
     else
     {
         printf("Server: The Winsock DLL status is %s.n", wsaData.szSystemStatus);
         // Create a new socket to receive datagrams on.
         ReceivingSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
         if (ReceivingSocket == INVALID_SOCKET)
         {
              printf("Server: Error at socket(): %ldn", WSAGetLastError());
              // Clean up
              WSACleanup();
              // Exit with error
              return -1;
         }
         else
         {
              printf("Server: socket() is OK!n");
         }
     }
}

这是 C# 代码，我尝试导入 DLL C++有人可以指出我应该如何处理由我的代码制作的示例代码：

public partial class Form1 : Form
    {
        [DllImport(@"C:UsersDocumentsVisual Studio 2010ProjectsServer_Receiver Solution DLLDebugServer_Receiver.dll", EntryPoint = "DllMain")]
        private static extern int ReceiverInformation();
        private static int ReceiverInformation(IntPtr hWnd)
        {
            throw new NotImplementedException();
        }
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            //textBox1.Text = "Hello";
            this.Close();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
        }           
    }

Answer 1

不要使用 printf 。将字符串传递给 C#。喜欢这个：

C++ DLL 代码片段如下：

extern "C" __declspec(dllexport) int Test(char* message, int length)
{
    _snprintf(message, length, "Test");
    return 1;
}

C# 代码段如下：

[DllImport(@"test.dll")]
private static extern int Test(StringBuilder sb, int capacity);
static void Main(string[] args)
{
    var sb = new StringBuilder(32);
    Test(sb, sb.Capacity);
    // Do what you need here. In your case, testBox1.Text = sb.ToString()
    Console.WriteLine(sb);
}

确保 StringBuilder 的容量适合从 DLL 导出输出的任何消息。否则，它将被截断。